JP3306729B2 - Microstrip antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna for a mobile station of a mobile communication system, and more particularly, to an antenna structure of a portable radio telephone having a structure in which the angle of the antenna changes depending on a use condition, so that the receiving sensitivity is affected. According to.

[0002]

2. Description of the Related Art FIG. 25 is a diagram showing an example of the configuration of a conventional portable radio telephone. In the figure, 29 is a whip antenna, 30 is a transmitter, 31 is a receiver, 32 is a dial unit, and 33 is a housing. In the portable radio telephone having such a structure, when the portable radio telephone is in the upright state as shown in FIG. 25, the whip antenna 29 operates as a vertically polarized antenna, and an omnidirectional radiation pattern is obtained in a horizontal plane.

However, in an actual call state, FIG.
As shown in FIG. 6, the portable wireless telephone is held by the user's hand 20 beside the human head 19, and the antenna is used with the antenna tilted from the vertical direction. Therefore, the polarization characteristics of the antenna have directivity not only for vertically polarized waves but also for horizontally polarized waves. For this reason, in a land mobile communication system using vertical polarization as the main polarization, the effective gain decreases with the inclination of the antenna.

[0004] In particular, in a mobile communication system using micro cells, which is regarded as a promising technique for improving the frequency utilization efficiency of mobile communication, a base station antenna is placed at a relatively low position (2 to 10 m above ground) on a road. It is assumed that the mobile radiotelephone is used under a propagation condition in which the mobile station and the base station are almost in sight. In such a line-of-sight propagation path, the degree of cross-polarization discrimination is extremely high.
It reaches as high as 15 dB.

Therefore, in the conventional portable radio telephone as shown in FIG. 25, the polarization characteristic fluctuation due to the inclination of the antenna appears as a large decrease in the effective gain, and the communication quality is largely deteriorated. FIG. 27 shows the characteristic of the effective gain with respect to the antenna tilt in the whip antenna system. As can be seen from the figure, when the antenna tilt angle reaches 90 degrees, the effective gain, that is, the reception level is about 14 dB.
Also decrease.

[0006]

The decrease in the effective gain of the antenna described above is based on the fact that the polarization characteristics of the antenna fluctuate according to the state of use. As a method for reducing artificial fluctuations in antenna polarization characteristics in such a portable radio telephone, a polarization diversity antenna configuration using orthogonal polarization as shown in FIG. 28 can be considered.

In FIG. 1, reference numeral 33 denotes a body of a portable radio telephone; 34, a radiating element of a microstrip antenna mounted on the back of the body 33; 35, a first port of the antenna element 34; The second port. The basic excitation modes of the microstrip antenna element 34 are contracted so as to be orthogonal to each other.
Therefore, independent antenna branches can be obtained by using these condensed modes as the diversity ports. (See Taga et al., "Study of Microstrip Diversity Antenna," Proc. ).

When this antenna element 34 is mounted on a radio body as shown in FIG. 28, the first port 35 of the antenna element 34 is provided when the body 33 is upright.
Are sensitive to vertical polarization. As the body 33 inclines from the vertical direction, the reception level at the first port 35 decreases, while the reception level at the second port 36 increases. When the inclination angle 37 is 45 ° from the vertical direction of the housing 33, the reception level of the first port 35 and the second port 3
6 is equal to, but lower by about 3 dB than, the reception level of the first port 35 when the housing 33 is upright.

When the inclination angle 37 is inclined to 45 ° or more, the reception level of the second boat 36 becomes higher.
Therefore, if the reception levels of these two antenna ports 35 and 36 are constantly monitored and a port with a high bell is selected, it is possible to prevent the reception level from being extremely lowered due to the inclination of the antenna.

[0010] However, such a diversity antenna configuration requires a reception level detector, a level determination device, and a switch for switching an antenna port. In the case of an analog system, switching noise of the switch becomes a problem. There was an undesired problem. Further, there has been a problem that the variation in the detection level due to aging of the reception level detector is large, and the selected antenna port may not always have the optimum polarization.

[0011] On the other hand, in the case of the digital system, the switching of the antenna ports may be performed in frame units, so that switching noise is not a problem. However, due to the variation of the reception level detector, the selected antenna port is not always optimally polarized. The problem of not always being true was inevitable. In addition, since there is an electrical antenna port switching method, a switching circuit is required, which is disadvantageous for miniaturization and low power consumption of a portable radio telephone.

The present invention does not require an electric circuit which is disadvantageous for downsizing and low power consumption of the portable radio, and the polarization characteristics of the antenna can be changed to the initial polarization even when the portable telephone is tilted. It is an object of the present invention to provide an antenna that returns to a state, thereby suppressing a change in the effective gain of the antenna and realizing a mobile phone having excellent call quality.

[0013]

According to the present invention, the above-mentioned object is solved by the means described in the claims. That is, the invention of claim 1 has a first dielectric substrate having at least one radiating element made of a metal film on one surface, a ground conductor made of a metal film on one surface, and a ground conductor formed on the other surface. In a microstrip antenna composed of a second dielectric substrate having a strip line composed of a metal film, a radiating element of the first dielectric substrate and a second dielectric substrate are provided.
Of being a dielectric substrate of stripline maintaining electromagnetic coupling, the first dielectric substrate antenna in the second dielectric substrate
Have a mechanism that can rotate around the burner axis of rotation, said antenna
The rotation axis is at a position off the center of gravity on the first dielectric substrate
Wherein the first dielectric substrate is rotated by gravity.
The radiation element is always sensitive to vertical polarization
The microstrip antenna is characterized in that the antenna faces in a direction of the microstrip.

According to a second aspect of the present invention, in the antenna according to the first aspect, the first dielectric substrate or the radiating member is provided.
A microstrip antenna characterized in that a weight is attached to the surface or side surface of the element . The invention of claim 3 is the invention according to claim 1 and claim 2 in which
Is a microstrip antenna in which the shape of the radiating element of the dielectric substrate is rectangular.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the antenna rotation axis deviates from a strip line provided on the second dielectric substrate, or the strip line. Is a microstrip antenna configured to be located outside a region extending in the longitudinal direction. According to a fifth aspect of the present invention, there is provided the first to fourth aspects of the present invention.
In the described invention, a microstrip antenna is provided in which one end of a strip line of a second dielectric substrate is formed in an arc shape.

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, one end of the strip line of the second dielectric substrate is formed in an arc shape, and one end of the strip line formed in an arc shape. Is a microstrip antenna connected to a strip line having an electrical length of approximately one-fourth of the used wavelength.

[0017]

When the microstrip antenna of the present invention is mounted on a housing of a portable radio and actually used, if the portable radio is tilted, the second dielectric substrate is also tilted at the same time. However, the first dielectric substrate, since the second dielectric substrate can be independently rotated, for example, such as providing the weight on the first dielectric substrate, a first dielectric antenna rotary shaft On board
By configuring the first dielectric substrate at a position deviated from the center of gravity, the first dielectric substrate can rotate around the antenna rotation axis and always maintain a constant position. At this time, since the antenna radiating element provided on the first dielectric substrate maintains electromagnetic coupling with the strip line provided on the second dielectric substrate, power is supplied by this. Therefore, the polarization characteristic of the antenna radiating element can always be directed in the vertical direction by using gravity. Hereinafter, the operation and the like of the present invention will be described in detail based on examples.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of the present invention,
(A) is a front view, (b) is a side view, and (c) is a bottom view, each of which is partially broken so that the internal structure can be seen. In the figure, 1 is a first dielectric substrate, 2 is a second dielectric substrate, 3 is an antenna radiating element having a rectangular shape formed of a metal film adhered to the surface of the first dielectric substrate 1,

Reference numeral 4 denotes a strip line made of a metal coating applied to the surface of the second dielectric substrate 2; 5, a ground conductor made of a metal coating applied to the back surface of the second dielectric substrate 2; Denotes an antenna plug, 7 denotes a weight provided on the first dielectric substrate 1, 8 denotes an antenna circuit axis provided at a position that is a center of the antenna radiating element 3, 9 denotes an antenna cover made of a dielectric material, and 10 denotes a antenna cover. An antenna rotating shaft support provided on the surface of the dielectric substrate 2;

Reference numeral 11 denotes an antenna rotating shaft support provided on the back of the antenna cover 9. The antenna rotating shaft 8 provided on the first dielectric substrate 1 and the antenna rotating shaft support provided on the second dielectric substrate 2. The first dielectric substrate 1 is overlaid on the second dielectric substrate 2 so that the unit 10 and the antenna rotation axis support 11 provided on the back of the antenna cover 9 are aligned with each other,
Further, the antenna cover 9 is formed on the first dielectric substrate 1.

The antenna radiating element 3 has an element length set so as to have an electrical length of about の of the resonance wavelength in consideration of the dielectric constant of the dielectric substrates 1 and 2, and is arranged above the microstrip line 4. I have. The high-frequency current input from the antenna plug 6 propagates through the microstrip line 4, and the electromagnetic radiation coupling between the microstrip line 4 and the antenna radiating element 3 is performed by electromagnetic coupling in the overlapping portion.
And resonance is obtained in a desired frequency band.

FIG. 2 shows the return loss of this embodiment, and it can be seen that good resonance characteristics are obtained. FIG. 3B shows a change in the frequency bandwidth at which the VSWR becomes 2 or less when the antenna radiating element 3 shown in FIG. 3A rotates around the antenna rotation axis 8. Approximately 10 MH at a rotation angle of the antenna radiating element of 60 °
It can be seen that a bandwidth of z has been obtained.

FIG. 4 shows changes in the radiation directivity of both vertically and horizontally polarized waves in a horizontal plane when the antenna radiating element 3 rotates about the antenna rotation axis 8. (B)
Approximately 2.0 dBd even when the rotation angle is 60 °
(Dipole ratio) is obtained, and even when the radiating element 3 rotates, the polarization characteristic when the rotation angle shown in (a) is 0 ° is maintained, and good radiation characteristics are realized. ing.

Further, when the antenna of the present invention is mounted on a portable radio as shown in FIG. 5A, the antenna radiating element is rotated by the weight 7. In the same figure, reference numeral 2 denotes a dielectric substrate of the antenna of the present invention, 4 denotes a strip line, 17 denotes a portable radio housing, and (a) shows a state where the portable radio housing 17 stands upright.

At this time, since the portable radio is upright, the weight 7 is located at the lower end of the antenna due to gravity, whereby the antenna radiating element 3 has sensitivity to vertical polarization. FIG. 5B shows an example of an actual use state of the portable wireless device, in which 19 is a human head of a user, and 20 is a hand of the user. At this time, the portable wireless device housing 17 is tilted at an angle of about 60 ° beside the head 19 of the user,

The antenna radiating element 3 is rotated by the weight 7 about the antenna rotation axis 8 as a center of rotation, and moves in a direction having sensitivity to vertical polarization as shown in FIG. That is, in the present embodiment, even if the inclination angle of the portable wireless device fluctuates artificially by the user, the antenna radiating element 3 always moves so as to be sensitive to vertical polarization, and the polarization characteristics are maintained. Therefore, the antenna effective gain can be kept constant.

FIGS. 6A and 6B show a second embodiment of the present invention. FIG. 6A is a front view, FIG. 6B is a side view, and FIG. 6C is a bottom view. As in the case of, each part is crushed so that the internal structure can be seen. In the drawing, 1 is a first dielectric substrate, 2 is a second dielectric substrate, 3 is an antenna radiating element having a rectangular shape formed of a metal coating adhered to the surface of the first dielectric substrate 1,

Reference numeral 4 denotes a strip line made of a metal coating applied to the surface of the second dielectric substrate 2, 5 denotes a ground conductor made of a metal coating applied to the back surface of the second dielectric substrate 2, and 6 Is an antenna plug, 7 is a weight provided on the first dielectric substrate 1, 8 is an antenna rotation axis provided at a position off the center of the antenna radiating element 3, 9 is an antenna cover made of a dielectric material, and 10 is An antenna rotation shaft support provided on the surface of the second dielectric substrate 2, 11 is an antenna rotation shaft support provided on the back of the antenna cover 9,

The antenna rotating shaft 8 provided on the first dielectric substrate 1, the antenna rotating shaft support 10 provided on the second dielectric substrate 2, and the antenna rotating shaft support 11 provided on the back of the antenna cover 9 are provided. The first dielectric substrate 1 is overlaid on the second dielectric substrate 2 so as to be aligned with each other, and the antenna cover 9 is further overlaid on the first dielectric substrate 1.

The antenna radiating element 3 has an element length set so as to have an electrical length of about １ ／ of the resonance wavelength in consideration of the dielectric constant of the dielectric substrates 1 and 2, and is arranged above the microstrip line 4. I have. The high-frequency current input from the antenna plug 6 propagates through the microstrip line 4, and the electromagnetic radiation coupling between the microstrip line 4 and the antenna radiating element 3 is performed by electromagnetic coupling in the overlapping portion.
And resonance is obtained in a desired frequency band.

FIG. 7 shows that when the antenna radiating element 3 rotates about the antenna rotation axis 8 as shown in FIG.
(B) shows a change in the frequency bandwidth at which the SWR becomes 2 or less. The rotation angle of the antenna radiating element 3 is about 80
°, a bandwidth of about 100 MHz is obtained, and the antenna radiating element has a VSWR of 2 or less as compared with the case where the antenna rotation axis 8 is set at the center of gravity of the antenna radiating element 3 shown in the first embodiment. It can be seen that both the rotation angle range and the bandwidth of No. 3 are significantly wider.

FIG. 8 shows changes in the radiation directivity of both vertical and horizontal polarized waves in a horizontal plane when the antenna radiating element 3 rotates about the antenna rotation axis 8. (B)
Approximately 2.0 dBd even when the rotation angle is 60 °
A directional gain of (dipole ratio) is obtained, and even when the radiating element 3 rotates, the polarization characteristic when the rotation angle shown in (a) is 0 ° is maintained, and good radiation characteristics are realized. Have been.

When the antenna of the present invention is mounted on a portable radio and used, the dielectric substrate 1 is rotated by the weight 7 as described in the first embodiment. Is rotated about the antenna rotation axis 8 as a center of rotation, always moves to have sensitivity to vertical polarization, and polarization characteristics are maintained. That is, even if the inclination angle of the portable wireless device fluctuates artificially by the user, a portable wireless device in which the antenna effective gain is constant can be realized.

FIGS. 9A and 9B are views for explaining a third embodiment of the present invention, wherein FIG. 9A is a front view, FIG. 9B is a side view, and FIG. 9C is a bottom view. In the drawing, 1 is a first dielectric substrate, 2 is a second dielectric substrate, and 3 is a surface of the first dielectric substrate 1. An antenna radiating element having a rectangular shape, made of a metal film, and a strip line 4 made of a metal film adhered on the surface of the second dielectric substrate 2,

Reference numeral 5 denotes a ground conductor made of a metal coating adhered to the back surface of the second dielectric substrate 2, 6 denotes an antenna plug, 7
Is a weight provided on the first dielectric substrate 1, 8 is an antenna rotation axis provided at the center of the antenna radiating element 3, 9 is an antenna cover made of a dielectric material, and 10 is provided on the second dielectric substrate 2. An antenna rotation shaft support provided on the surface of the second dielectric substrate 2 at a position deviating from a straight line passing through the longitudinal direction of the strip line 4, and 11 is an antenna rotation shaft support provided on the back surface of the antenna cover 9. ,

The antenna rotating shaft 8 provided on the first dielectric substrate 1, the antenna rotating shaft support 10 provided on the second dielectric substrate 2, and the antenna rotating shaft support 11 provided on the back of the antenna cover 9 are provided. The first dielectric substrate 1 is overlaid on the second dielectric substrate 2 so as to be aligned with each other, and the antenna cover 9 is further overlaid on the first dielectric substrate 1.

The antenna radiating element 3 has an element length set so as to have an electrical length of about の of the resonance wavelength in consideration of the dielectric constant of the dielectric substrates 1 and 2, and is arranged above the microstrip line 4. I have. The high-frequency current input from the antenna plug 6 propagates through the microstrip line 4, and the electromagnetic radiation coupling between the microstrip line 4 and the antenna radiating element 3 is performed by electromagnetic coupling in the overlapping portion.
And resonance is obtained in a desired frequency band.

FIG. 10 (b) shows a change in the frequency bandwidth in which the VSWR becomes 2 or less when the antenna radiating element 3 rotates about the antenna rotation axis 8 as shown in FIG. 10 (a). Approx. 10 MHz even at a rotation angle of about 75 °
Is obtained, and the rotation angle range in which the VSWR is 2 or less is wider than that of the first embodiment in which the antenna rotation axis is provided at the position that becomes the center of gravity of the antenna radiating element. . Further, in the second embodiment, since the antenna rotation axis is provided at a position off the center of gravity of the antenna radiating element 3,

When the antenna radiating element is rotated, the radius of rotation becomes large, and when the antenna is mounted on a portable device, it is necessary to enlarge the casing of the portable radio device, which is disadvantageous for downsizing the portable device. However, since the antenna of the present invention has the antenna rotation axis provided at the center of the antenna radiating element as in the first embodiment, the radius of rotation when the antenna radiating element rotates is small, which is advantageous for miniaturization of a portable device. is there.

FIG. 11 shows a vertical axis in a horizontal plane when the antenna radiating element 3 rotates around the antenna rotation axis 8.
It shows the change in the radiation directivity of both horizontal polarized waves.
Even when the rotation angle shown in (b) is 60 °, the maximum is about 0 dB.
A directivity gain of d (dipearl ratio) is obtained, and even when the radiating element 3 rotates, the polarization characteristics when the rotation angle shown in (a) is 0 ° are maintained, and good radiation characteristics are realized. Have been.

When the antenna of the present invention is mounted and used in a portable radio, the dielectric substrate 1 is rotated by the weight 7 as described in the first embodiment, so that the antenna radiating element 3 The antenna is rotated about the antenna rotation axis 8 as a rotation center, and always moves so as to have sensitivity to vertical polarization, thereby maintaining polarization characteristics. That is, even if the inclination angle of the portable wireless device fluctuates artificially by the user, a portable wireless device in which the antenna effective gain is constant can be realized.

FIG. 12 is a view for explaining a fourth embodiment of the present invention, wherein reference numerals 1 and 2 denote a dielectric substrate, and 3a denotes a dielectric substrate 2.
Formed of a metal film adhered to the surface of
Radiating element having a length shorter than / 2, 5 is a ground conductor, 6
Is an antenna plug, 7 is a weight, 8 is an antenna rotating shaft, 9 is an antenna cover made of a dielectric material, 10 is an antenna rotating shaft support provided on the dielectric substrate 1,

Numeral 11 denotes an antenna rotating shaft supporting portion provided on the antenna cover 9;
Reference numeral 15 denotes a high-frequency line connected to the ends 12 and 13 of the feeder line 16 and having an electrical length of about １ ／ of the wavelength,
Are mounted on the dielectric substrate 1 such that the antenna rotating shaft 8 is fitted into the antenna rotating shaft support and is rotatable. The other end of the antenna rotation shaft is fitted into the rotation support portion 11 of the antenna cover, and is positioned so that the dielectric substrate 1 is rotatable.

With this configuration, the high frequency input from the antenna plug 6 passes through the high-frequency line 19, the feed line 16, and the high-frequency line 14 and passes through the high-frequency line 1.
4 at the end. Since the electric length of the high-frequency line 14 is set to approximately １ ／ wavelength, the amplitude of the standing wave current at the position of the feed line 16 becomes substantially maximum. Since the radiating element 3a formed on the surface of the dielectric substrate 1 is disposed above the position of the feeder line 5, a feed current on the feeder line 16 is induced on the radiator 3a by electromagnetic coupling.

The element length of the radiating element 3a is determined by taking into account the dielectric constant of the dielectric substrates 1 and 2 (usually 1 / the wavelength).
By setting the length to be shorter than 2, resonance can be obtained in a desired frequency band. FIG. 13 shows the return loss characteristics of the present example, and it can be seen that good resonance characteristics are obtained.

At this time, a sinusoidal current is induced in the radiation element 3a, and the radiation element 3a operates as a half-wavelength dipole antenna element having a microstrip structure. FIG. 14 shows the vertically polarized radiation directivity in the horizontal plane of the antenna of this embodiment.
A maximum directional gain of about 5.6 dBi is obtained, and good radiation characteristics are realized.

Further, since the dielectric substrate 1 of the antenna has a structure in which it can freely rotate 360 ° about the rotation axis of the antenna, the antenna is mounted on a portable radio as shown in FIG. In this case, the dielectric substrate 1 rotates so that the weight 7 is below the center of rotation and stops at a fixed position. In FIG. 15A,

Reference numeral 18 denotes an antenna according to the present invention, and 17 denotes a radio body, which shows a state where the radio body 17 is upright. At this time, the weight 7 is located at the lowermost portion of the antenna as shown in the figure, and as a result, the radiating element 3a on the dielectric substrate 1 is oriented in a direction sensitive to vertical polarization. In FIG. 2B, reference numeral 19 denotes a human head, 2
Reference numeral 0 denotes a hand, and the radio body 17 is slanted beside the human head 19.

At this time, the dielectric substrate 1 is rotated by the weight 7 about the antenna rotation axis as a center of rotation, and the radiating element 3a is inclined in a direction having sensitivity to vertical polarization as shown in the figure. That is, in this embodiment, the radiating element 3a always moves so as to have sensitivity to vertical polarization regardless of the inclination of the portable radio body, and the polarization characteristics are maintained.

In the present invention, since the feed line 16 is formed in an arc shape, a constant excitation condition is maintained even when the radiating element rotates, and therefore, the radiation directivity shown in FIG. 14 is maintained. In addition, since the operation radiating element 3a is configured to be excited by the space feeding with the feed line 16, there is no generation of noise due to the rotating operation of the radiating element.

FIG. 16 is a view for explaining a fifth embodiment of the present invention. The structure and the like are almost the same as those in FIG. 12 except that a radiating element 3b is added. The high frequency input from the antenna plug 6 passes through the high-frequency line 15, the feed line 16, and the high-frequency line 14 and passes through the high-frequency line 1.
4 at the end.

Since the electrical length of the high-frequency line 14 is set to approximately １ ／ wavelength, the amplitude of the standing wave current at the position of the feed line 16 becomes substantially maximum. Since the radiating element 3a formed on the surface of the dielectric substrate 1 is arranged above the position of the feeder line 16, a feed current on the feeder line 16 is induced on the radiating element 3a by electromagnetic coupling.

By setting the element length of the radiating element 3a to the length of a standing wave having a resonance wavelength in consideration of the dielectric constant of the dielectric substrates 1 and 2, resonance can be obtained in a desired frequency band. The radiating element 3b is set to have a resonance wavelength different from that of the radiating element 3a, but the feed current on the feed line 16 at the frequency corresponding to the resonance wavelength is equal to the radiating element 3a.
Via the radiating element 3b. That is, a radiation element that operates at two different frequencies can be formed.

FIG. 17 is a view for explaining the sixteenth embodiment, and shows another example of forming a radiating element operating at two frequencies. The radiating element 3 is placed on the radiating element 3c of FIG.
An antenna current is induced via a. Therefore, the resonance frequency determined by the length of the radiating element 3a and the radiating element 3
A radiating element operating at two resonance frequencies determined by the length including c and the radiating element 3a can be formed.

At this time, a sine-wave standing wave current is induced in each of the radiating elements 3a and 3c and the radiating elements including the radiating elements 3a and 3c, and operates as a dipole antenna element having a microstrip structure. The radiation directivity similar to the radiation directivity shown in FIG.

Further, since the dielectric substrate 1 of the antenna has a structure in which the dielectric substrate 1 can freely rotate by 360 ° about the rotation axis of the antenna, the radiating elements 3a and 3c are formed as described in the first embodiment. Due to the weight 7, the portable wireless device always moves to have sensitivity to vertical polarization regardless of the inclination of the body of the portable wireless device, and the polarization characteristic is maintained.

Also in the embodiment, since the feed line 16 is formed in an arc shape, a constant excitation condition is maintained even when the radiating element rotates, so that the same radiation directivity as shown in FIG. 14 is maintained. . Further, since the radiating element 3a is actuated to be excited by the space feeding with the feed line 16, there is no generation of noise due to the rotating operation of the radiating element.

FIG. 18 is a view for explaining a seventh embodiment of the present invention, in which dielectric substrates 1 and 2 are formed in a circular shape centering on a fitting portion between the antenna rotation axis and the dielectric substrate 2. The example in the case where it was performed is shown. Because of this 43, the antenna can be configured by reducing the weight of the dielectric substrate 2 while maintaining necessary functional operations.

FIG. 19 is a view for explaining an eighth embodiment of the present invention. The structure of the dielectric substrate 1 shown in FIG. 18 is made asymmetrical with respect to the projection 12 of the dielectric substrate as a center point. It shows an embodiment in the case where it is performed. The figure shows a case where the shape of the dielectric substrate 1 is T-shaped. By forming the dielectric substrate 1 in this manner, the dielectric substrate 1
Since the device itself can be configured like a pendulum, a structure in which the weight 7 is eliminated can be provided. Also in this embodiment,
Its operation characteristics are the same as those of the above embodiment.

FIG. 20 is a view for explaining a ninth embodiment of the present invention. In FIG. 20, reference numeral 8a denotes a rotating shaft penetrating the dielectric substrate 1, and 9a denotes an antenna made of a dielectric housing the antenna of the present invention. It is a cover. The antenna cover 9a is arranged such that the rotating shaft 8a is sandwiched between the antenna rotating shaft support 11 provided on the antenna cover 9a and the antenna rotating shaft support Ic provided on the surface of the dielectric substrate 1. , 2 are fixed so as to overlap.

The dielectric substrate 1 is rotated by 360 around the rotation axis 8a.
When the present antenna is mounted on the body of the portable wireless device, the radiating element 3a operates so as to always maintain a constant polarization characteristic by the action of the weight 7. In this embodiment, the other embodiment mainly has the antenna rotation axis fixedly provided on the dielectric plate 1, whereas the dielectric plate 1
Is different from the other embodiments in that it can rotate.

FIG. 21 is a view for explaining a tenth embodiment of the present invention. A cap 21 made of metal or the like is embedded in the dielectric substrate and the antenna rotation shaft support portion of the antenna cover. 1 shows a configuration for supporting the above. With such a structure, it is possible to reduce abrasion of the antenna rotating shaft support portion and to prolong the life of the antenna.

FIG. 22 is a view for explaining an eleventh embodiment of the present invention. In FIG. 22, the antenna rotating shaft support provided at the center of the dielectric substrate 1 is provided with a length in the longitudinal direction of the radiating element 3a. It shows an example of a case where it is configured to be provided at a position deviated from an extension of a bisected center line. The position of the center line that bisects the longitudinal length of the radiating element 3a is configured to be at a position offset from a portion directly above the feed line 16, and changes the coupling state between the feed line 16 and the radiating element 3a. be able to.

That is, the input impedance characteristics viewed from the antenna plug can be adjusted, and the antenna can be operated under the best coupling conditions. Similarly, the coupling condition can be adjusted by moving the position of the radiating element 3a closer to or farther from the antenna rotating shaft support of the dielectric substrate 1.

FIG. 23 is a view for explaining a twelfth embodiment of the present invention, and shows an example of a shape of a radiating element which can be used in the present invention. FIG. 7A shows a case where the radiating element 3a is rectangular, which has been described in the above embodiment.
FIG. 3B shows a case where the radiating element 3d has a bent band-like element shape, and the operating frequency of the antenna can be reduced without changing the dimensions of the dielectric substrates 1 and 2.

In other words, it is effective for downsizing the antenna. It is also effective when cross polarization characteristics are required. FIG. 9C shows a case where the radiation element 3e is curved and band-shaped, and is effective in obtaining desired polarization characteristics and radiation directivity. In any of these cases, the positional relationship between the feedability 16 and the antenna element is arranged in an optimal positional relationship as described in the description of the tenth embodiment.

FIG. 24 is a view for explaining a thirteenth embodiment of the present invention, in which a high-frequency line 14 having an electrical length of about の of the wavelength connected to one end of an arc-shaped feeder line 16 and A line 15 for electrically connecting the other end of the arc-shaped power supply line 16 and the antenna plug 6 is provided on the back surface of the ground conductor 5 attached to the back surface of the dielectric substrate 2. It is attached to the back surface of the dielectric substrate 23, and is sandwiched by the dielectric substrate 24 on which the ground conductor 25 is attached, and is configured as a triplate structure high-frequency line.

The electric power supply line 16 is electrically connected to the arc-shaped power supply line 16 by a conductor pin 22 penetrating through the dielectric substrate 2 and the dielectric substrate 23 through a small hole provided in the ground conductor 5. With such a structure, the influence of mutual coupling between the high-frequency lines 14 and 15 and the rotating radiating element 3a can be eliminated, and even when the radiating element 3a is rotated to any arbitrary position. Good operating characteristics can be obtained.

The embodiment described above shows an embodiment in which the feeding circuit is constituted by a microstrip line made of a metal film formed on the surface of the dielectric substrate 2 in an arc shape around the antenna rotation axis. However, a similar polarization tracking antenna can be realized by forming a slot on the surface of the dielectric substrate 2 and using slot coupling instead of the microstrip line structure such as the feed line 16.

This also applies to the configuration of the radiating element. The thickness of the dielectric plate in the antenna of the present invention, together with the dielectric constant of the dielectric, the area where the radiating element and the feeding element face each other, are one factor that determines the feeding loss, and there is no absolute limitation, but the loss is more than necessary. In general, it is desirable that the wavelength be equal to or less than the wavelength of the electromagnetic wave used.

Further, in all the above embodiments, the case where the shape of the dielectric substrate 1 and the dielectric substrate 2 is rectangular or circular has been described. However, the dielectric substrate of the present invention is not limited to this. For example, it goes without saying that an ellipse or another shape is also included in the present invention.

In all of the above embodiments, the case where the surface of the first dielectric substrate having no radiating element and the surface of the second dielectric substrate having the strip line face each other has been described. Similar antenna characteristics can be obtained even when the surface of the first dielectric substrate having the radiating element and the surface of the second dielectric substrate having the strip line face each other.

In the above embodiment, the case where the shape of the antenna radiating element is mainly rectangular has been described. However, the shape of the antenna radiating element 3 of the present invention is not limited to this. In the present invention, the existing antenna technology applied to the antenna structure of the present invention, such as the one that is cut down to reduce the size, the one that adds a parasitic element to achieve dual frequency use and the wider band, etc., is also included in the present invention. Of course it is included.

In the above embodiment, the case where the antenna rotating shaft is held by the antenna cover and the dielectric substrate has been described. However, the rotating structure of the antenna radiating element of the present invention is not limited to this. It goes without saying that the present invention also includes a rotating structure in which an antenna rotation axis is provided on one of the surface of the antenna radiating element and the surface of the dielectric substrate and one of the dielectric substrate and the antenna cover is supported. .

Further, in the above embodiment, the case where the weight is provided on the dielectric substrate has been described. However, the configuration of the weight according to the present invention is not limited to this. A structure provided on the surface or side surface of the element is also conceivable.

Further, in the above embodiment, the case where a member for mechanically supporting the dielectric substrate at the center of rotation is provided is described. However, the present invention is not limited to this. Without providing, for example, filling the antenna in a sealed container and filling the nuclear container with fluid,
It is needless to say that the present invention includes a structure in which the dielectric plate provided with the radiating element can rotate.

[0077]

As described above, according to the present invention, even when the inclination angle of the portable radio device is artificially changed by the use condition of the user, the polarization characteristic of the antenna does not change.
This is effective as an antenna for a portable wireless device in which the antenna effective gain is always constant. Therefore, it is possible to realize a portable wireless device antenna having a high effective gain, which is useful in a micro-cell type mobile communication system having a high degree of cross-polarization discrimination with a line of sight road or the like as a main wireless zone.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram illustrating return loss of the antenna of the present invention.

FIG. 3 is a diagram illustrating a change in a bandwidth in which the VSWR becomes 2 or less when the antenna radiating element of the antenna according to the first embodiment of the present invention rotates.

FIG. 4 is a diagram showing radiation directivity of both vertical and horizontal polarizations of the antenna of the first embodiment.

FIG. 5 is a diagram showing mounting of the antenna of the first embodiment on a portable wireless device and a call state;

FIG. 6 is a diagram showing a second embodiment of the present invention.

FIG. 7 is a diagram showing a change in bandwidth when the antenna radiating element of the second embodiment rotates.

FIG. 8 is a diagram illustrating the radiation directivity of both vertical and horizontal polarizations of the antenna according to the second embodiment.

FIG. 9 is a diagram showing a third embodiment of the present invention.

FIG. 10 is a diagram showing a change in bandwidth when the antenna radiating element of the third embodiment rotates.

FIG. 11 is a diagram illustrating radiation directivity of both vertical and horizontal polarizations of the antenna according to the third embodiment.

FIG. 12 is a diagram for explaining a fourth embodiment of the present invention.

FIG. 13 is a diagram illustrating a return loss characteristic of the fourth embodiment.

FIG. 14 is a diagram illustrating a vertically polarized radiation directivity in a horizontal plane of the antenna of the fourth embodiment.

FIG. 15 is a diagram illustrating an example of mounting the antenna of the fourth embodiment on a portable wireless device and an example of use;

FIG. 16 is a diagram for explaining a fifth embodiment of the present invention.

FIG. 17 is a diagram illustrating a sixth embodiment of the present invention.

FIG. 18 is a diagram for explaining a seventh embodiment of the present invention.

FIG. 19 is a diagram for explaining an eighth embodiment of the present invention.

FIG. 20 is a diagram illustrating a ninth embodiment of the present invention.

FIG. 21 is a diagram for explaining a tenth embodiment of the present invention.

FIG. 22 is a diagram for explaining an eleventh embodiment of the present invention.

FIG. 23 is a diagram for explaining a twelfth embodiment of the present invention.

FIG. 24 is a diagram for explaining a thirteenth embodiment of the present invention.

FIG. 25 is a diagram illustrating an example of a configuration of a conventional portable wireless telephone.

FIG. 26 is a diagram illustrating a state in which the portable wireless telephone is actually used.

FIG. 27 is a diagram illustrating a relationship between an antenna tilt and an effective gain.

FIG. 28 is a diagram illustrating an example of a configuration of a polarization diversity antenna using orthogonal polarization.

[Explanation of symbols]

1, 2, 23, 24 Dielectric substrate 3, 3a to 3c Antenna radiating element 4 Microstrip line feed line 5 Ground conductor 6 Antenna plug 7 Weight 8, 8a Antenna rotation axis 9 Antenna cover 10 Provided on dielectric substrate 1 Antenna rotation axis support 11 Antenna rotation axis support provided on antenna cover 9 12, 13 Feed line end 14, 15 High-frequency line 16 Feed line 17 Radio housing 18 Antenna 19 Human head 20 User's hand 21 Metal cap 22 Conductor pin

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tokio Taga 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Keizo Chief 1-16-1 Uchisaiwaicho, Chiyoda-ku, Tokyo Japan (56) References JP-A-2-214205 (JP, A) JP-A-62-1304 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04Q 3 / 00-3/46 H04Q 13/08

Claims (6)

(57) [Claims] A first dielectric substrate having at least one radiating element made of a metal film on one surface; a grounding conductor made of a metal film on one surface;
In a microstrip antenna made of a second dielectric substrate having a strip line made of a metal film on the other surface, a radiating element of the first dielectric substrate and a strip line of the second dielectric substrate are electromagnetically coupled. while maintaining, the first dielectric substrate have a second dielectric mechanism capable of rotating <br/> rotation around the antenna rotary shaft on the substrate, wherein the antenna rotary shaft is said first dielectric substrate The upper center of gravity
And the first dielectric substrate is rotated by gravity.
The radiating element is always oriented in a direction sensitive to vertical polarization.
Ku, microstrip antenna, characterized in that. 2. The first dielectric substrate or the radiator
The microstrip antenna according to claim 1 , wherein a weight is attached to a surface or a side surface of the element . 3. The microstrip antenna according to claim 1, wherein the radiating element of the first dielectric substrate has a rectangular shape. 4. A structure in which the axis of rotation of the antenna is at a position off the strip line provided on the second dielectric substrate or at a position outside a region where the strip line extends in the longitudinal direction. The microstrip antenna according to claim 1. 5. The microstrip antenna according to claim 1, wherein one end of the strip line of the second dielectric substrate is formed in an arc shape. 6. An end of a strip line of a second dielectric substrate is formed in an arc shape, and a strip line having an electrical length of approximately one-fourth of a wavelength used is connected to one end of the strip line formed in an arc shape. The microstrip antenna according to claim 1, wherein: